Was experimenting with BTP v.1.0.15 and as I deleted an ingredient this error message appeared and the program crashed: (with a Red 'X') "An exception of class NilObjectException was not handled. The application must shut down." I'm using WindowsXP SP 2.

First, I can't see how I did anything wrong, so there might be a bug in your program that caused that.

Second, when I restarted the program, it started with a blank session, of course, and since I had not saved my experimental session, I guess it was lost unless BTP periodically saves data in case of a crash. Couldn't find anything in the User's Guide about that, so I presume it isn't a feature. I therefore suggest that in a future release, BTP should create a backup file and automatically do a save every so often (perhaps according to a user's preference settings) in case the program or computer crashes or the power suddenly goes off. Upon restarting the program, it would have a way to know if it was not normally closed at last exit, and ask if the user would like to resume with the unsaved session. My word processor does that sort of thing, and it has helped me many times that way, and it will polish your program.

I don't normally use sugar as an ingredient, but wanted to see how much of an impact it has on alcohol content since I use it as a primer.

When the program crashed, others that were running -- Netscape, Zone Alarm, etc. -- were unafffected. I restarted the program and tried to duplicate it by adding sugar and then deleting sugar, but the program ran fine the second time. I'll be sure to let you know if and when I have any further problems. I'm curious to know whether that is one of your program's error messages, or if it is a Windows error message.